Several trends presently exist in the semiconductor and electronics industry. One of these trends is that recent generations of portable electronic devices are using more memory than previous generations. This increase in memory allows these new devices to store more data, such as music or images, and also provides the devices with more computational power and speed.
Dynamic random access memory (DRAM) is one type of random access memory where individual bits of data are stored in separate capacitors. Because the capacitors leak charge, any data stored in a capacitor will fade unless it is refreshed periodically. Because of this characteristic, a DRAM is a dynamic memory, as opposed to SRAM and other types of static memory. When compared to SRAM, one advantage of DRAM is that it can have very high densities because of its simplistic memory cell structure.
In many arenas, DRAM is often a relatively affordable solution when large amounts of data storage are desired. This is because DRAMs is often relatively dense compared to other types of memory, such as static random access memory (SRAM). In other words, the capacitive elements that make up a DRAM array can be packed together tightly, such that many cells can be squeezed into a small area.
While DRAM is relatively dense, it suffers from a drawback in that it may not be compatible with manufacturing flows. For example, one type of DRAM is a trench capacitor DRAM, where trench capacitors that act as memory elements are etched into a silicon substrate. Generally, these trench capacitors would add extra mask steps in a manufacturing flow, and as such, are not typically included in these flows. In addition, if DRAM is to continue to be an attractive technology (i.e., dense), designers will likely want it to remain dense in comparison to other types of memory.
Therefore, a need has arisen to provide systems and methods relating to relatively dense memory devices that can be integrated into manufacturing flows.